1. Field of the Invention
The present invention relates to fuel injectors, and, more particularly, to a dual fuel fuel-injector 1. The dual fuel fuel-injector can be used, for example, with pilot injection engines, including the type that in addition to pilot injection operation with burnable fuel (and a diesel or heavy oil pilot injection) provide a pure diesel or heavy oil operation. Instead of heavy oil, bio-oil or bio fuel may be used.
2. Description of the Related Art
Gaseous fuels are increasingly gaining importance in the (large) engine sector, in particular with stationary engines for power generation. Natural gas for example, is ideally suited for economical and environmentally friendly engine operation due to its excellent availability and its excellent emission potential compared to diesel fuel.
With dual fuel fuel-injectors of this type, including indirectly controlled injectors (according to the known control principle of “pilot valve-actuator-control chamber”) that use liquid fuel as the control fluid not only for control of a liquid fuel nozzle needle, but also for control of at least one gas nozzle needle, leakage occurs regularly, generally on the guides of the gas nozzle needles. Especially in the case of multi-component multi-needle nozzles, the necessity of collecting and discharging such gas-containing liquid leakage from the fuel injector causes considerable constructional effort.
What is needed in the art is a dual fuel fuel-injector on which treatment of mixed leakage is easily possible from a design point of view.